// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/gl/scoped_cgl.h"
#include "base/logging.h"

namespace gfx {

ScopedCGLSetCurrentContext::ScopedCGLSetCurrentContext(CGLContextObj context)
{
    CGLContextObj previous_context = CGLGetCurrentContext();
    // It is possible for the previous context to have a zero reference count,
    // because making a context current does not increment the reference count.
    // In that case, do not restore the previous context.
    if (previous_context && CGLGetContextRetainCount(previous_context)) {
        previous_context_.reset(previous_context, base::scoped_policy::RETAIN);
    }
    CGLError error = CGLSetCurrentContext(context);
    DCHECK_EQ(error, kCGLNoError) << "CGLSetCurrentContext should never fail";
}

ScopedCGLSetCurrentContext::~ScopedCGLSetCurrentContext()
{
    CGLError error = CGLSetCurrentContext(previous_context_);
    DCHECK_EQ(error, kCGLNoError) << "CGLSetCurrentContext should never fail";
}

} // namespace gfx
